Lub tshuab hluav taws xob carbon steel tuaj yeem ua kom muaj sia nyob ntawm cov txheej txheem acidic me ntsis -xws li dilute hydrochloric acid ntxuav- los ntawm txheej nws sab hauv nrog cov txheej txheem nyias nyias - cov hlau tsis muaj zog. Cov txheej txheem electroless npib tsib xee tau ntev tau siv rau lub hom phiaj no, tab sis ib qho kev hloov tshiab tshiab nrog cov me me ntawm boron yog qhov nyiam rau kev xa cov denser, nyuaj, thiab ntau cov kua qaub- tiv thaiv kev tiv thaiv.
Kev loj hlob txaus siab nyob rau hauvelectroless Ni-P-B plating steel exchanger me ntsis aciddaim ntawv thov cuam tshuam txog kev lag luam dav dav rau kev txuas cov cuab yeej siv lub neej yam tsis tau txav tam sim mus rau cov khoom kim heev- alloy siv.
Vim li cas Mildly Acid Service Damages Steel Exchangers
Cov pa roj carbon steel kub exchangers tseem txaus nyiam vim yog:
Tus nqi khoom qis
Zoo mechanical zog
Yooj yim ntawm fabrication
Zoo heev thermal conductivity
Txawm li cas los xij, txawm tias dilute acidic ib puag ncig tuaj yeem maj mam tua cov hlau ntog.
Cov kev pabcuam corrosive feem ntau muaj xws li:
Dilute hydrochloric acid ntxuav
Sulfuric acid yaug cov kwj deg
Acidified txheej txheem dej
Pickling rov qab systems
Tsawg-kub tshuaj ntxuav circuits
Yog tsis muaj kev tiv thaiv, carbon steel hauv cov tshuab no yuav muaj kev paub txog:
General corrosion
Pitting
Tubewall thinning
Hlau paug ntawm cov txheej txheem kua
Rau ntau cov nroj tsuag, kev hloov pauv nrog cov khoom sib txawv xws li Hastelloy lossis titanium yog qhov nyuaj rau kev lag luam. Cov txheej tiv thaiv yog li ntawd nyob hauv ib qho tseem ceeb hauv nruab nrab.
Dab tsi yog Electroless Nickel - Phosphorus -Boron Plating?
Electroless npib tsib xee-phosphorus- boron plating yog cov tshuaj pleev xim hlau txheej uas siv tsis muaj hluav taws xob sab nraud.
Tsis zoo li cov pa electroplating, cov deposition tshwm sim uniformly hla txhua qhov chaw ntub dej los ntawm cov tshuaj tiv thaiv autocatalytic.
Qhov no tso cai rau cov txheej tuab zoo ib yam txawm tias sab hauv:
Me - txoj kab uas hla
Qhov muag qhov muag
Complex exchanger geometry
Sab hauv crevices
Lub resulting txheej combines:
Nickel
Phosphorus
Ntxiv me me ntawm boron
Qhov sib ntxiv ntawm boron tau hloov pauv cov microstructure thiab kev ua haujlwm ntawm cov txheej txheej deposited.
Yuav Ua Li Cas Boron Txhim Kho Cov Txheej Txheem
Ib txwm siv hluav taws xob tsis muaj npib tsib xee- phosphorus txheej twb muab kev tiv thaiv corrosion zoo, tab sis qhov sib ntxiv ntawm boron qhia ntau yam kev txhim kho tseem ceeb.
Mixed Amorphous thiab Nanocrystalline Structure
Cov npib tsib xee-phosphorus-boron deposit tsim ib qho kev sib xyaw amorphous thiab nanocrystalline microstructure.
Cov qauv no pab txhawb rau:
Txo porosity
Qhov ceev dua
Txhim kho nto continuity
Kev tiv thaiv ntau dua
Porosity yog txo qis dua piv rau cov pa electroless Ni-P txheej, txo qhov yuav ua rau cov kua qaub nkag mus txog cov hlau substrate.
Ib daim tawv nyias, iav ntawm npib tsib xee-boron hloov cov hlau pheej yig mus rau hauv cov kua qaub uas muaj peev xwm ua kom muaj sia nyob uas yuav txwv tsis pub haus cov hlau tsis muaj kev tiv thaiv sai.
Hardness txhim kho tom qab kev kho cua sov
Ib qho txiaj ntsig tseem ceeb tshaj plaws ntawm EN-P-B txheej yog lawv lub peev xwm los txhim kho qhov nyuaj siab heev tom qab kev kho cua sov.
Cov ntawv tshaj tawm -kub- kev kho mob hardness yuav siab tshaj:
>1000 HV>1000\ HV>1000 HV
Qhov kev txhim kho hardness no txhim khu kev tiv thaiv rau:
Kev puas tsuaj
Kev yaig
Slurry hnav
Flow-ua rau ntog puas tsuaj
Rau cov neeg sib pauv tuav cov kua qaub me me uas muaj cov khib nyiab tshem tawm, qhov kev hnav ntxiv no ua rau muaj txiaj ntsig tshwj xeeb.
Corrosion Protection Mechanisms
Cov txheej txheem feem ntau yog txheej thaiv txheej cais cov hlau substrate los ntawm cov txheej txheem acidic kua.
Resistance to Dilute Non-Oxidizing Acids
Electroless Ni-P-B ua tau zoo tshwj xeeb hauv:
Dilute sulfuric acid
Dilute hydrochloric acid
Tsawg-kub tsis yog- oxidizing acid pab
Cov txheej txheem qeeb corrosion los ntawm kev txwv cov electrolyte nkag mus rau hauv cov hlau hauv qab.
Galvanic tiv thaiv ntawm qhov tsis xws luag
Yog hais tias microscopic pinholes los yog txheej discontinuities tshwm sim, npib tsib xee tuaj yeem muab kev tiv thaiv galvanic tsawg rau cov hlau nyob ze nyob rau hauv qee yam mob.
Qhov no pab ua kom qeeb hauv zos nres ib puag ncig me me txheej tsis zoo.
Txawm hais tias tsis muaj kev tiv thaiv kev puas tsuaj, cov txheej txheej plated tau nthuav dav kev sib hloov ua haujlwm lub neej piv nrog cov hlau liab qab.
Yog vim li cas Uniform Thickness Matters nyob rau hauv Thaum tshav kub kub Exchangers
Thaum tshav kub kub exchangers muaj ntau geometrically nyuaj qhov chaw uas nyuaj rau lub tsho tiv no uniformly nrog cov pa txoj kev.
Electroless deposition muaj qhov zoo tshaj plaws vim tias cov txheej txheem coats:
Tube interiors tusyees
Tube nplooj ntawv tsis tu ncua
Flow passages uniformly
Internal ces kaum tsis muaj ntug buildup
Uniformity txo qis qhov chaw tsis muaj zog qhov twg qhov chaw corrosion tuaj yeem pib.
Cov yam ntxwv no muaj txiaj ntsig tshwj xeeb hauv lub plhaub - thiab - tube exchangers qhov twg kev nkag mus rau kev tshuaj xyuas thiab kho yuav raug txwv.
Economic Advantages Over Solid Alloy Tsim
Rau cov kev pabcuam corrosive me me, cov khoom siv nickel alloys lossis titanium exchangers tej zaum yuav yog technically ntau dhau.
Electroless Ni-P-B txheej tso cai rau cov khoom siv hlau ua kom tiav:
Lub neej ua haujlwm ntev dua
Txo kev tu ntau zaus
Txhim kho corrosion kuj
Tus nqi qis dua
Txoj kev yog tshwj xeeb tshaj yog txaus nyiam rau:
Cov peev nyiaj- txwv cov nroj tsuag
Retrofit tej yaam num
Cov txheej txheem thib ob
Nruab nrab -kub acid pab
Nyob rau hauv ntau zaus, txheej ib tug uas twb muaj lawm exchanger nqi tsuas yog ib feem ntawm kev hloov nws nrog ib tug tag nrho alloyed tsim.
Kub thiab tshuaj lom neeg txwv
Txawm hais tias nws qhov zoo, electroless npib tsib xee -phosphorus- boron plating tsis haum rau txhua qhov chaw corrosive.
Kub txwv
Txheej txheej feem ntau tseem siv tau txog li ntawm kwv yees li:
400∘C400^\\circ C400∘C
Saum toj no ntau yam:
Cov qauv kev ruaj ntseg txo qis
Kev pheej hmoo oxidation nce
Adhesion yuav deteriorate
Cov khoom siv tshuab tuaj yeem hloov pauv
rhiab heev rau Oxidizing Acids
Cov txheej kuj tsis tsim nyog rau oxidizing acids los yog aggressive chemical systems uas tua nickel ncaj qha.
Teeb meem ib puag ncig muaj xws li:
Concentrated nitric acid
Muaj zog oxidizing chlorides
Qee cov tshuaj complexing
Ammoniacal chemistry
Nyob rau hauv cov xwm txheej no, tus nqi corrosion tuaj yeem nce sai.
Ib qho tseem ceeb hauv nruab nrab rau kev lag luam
Lub zog ntawmelectroless Ni-P-B plating steel exchanger me ntsis acidthev naus laus zis nyob rau hauv nws lub peev xwm los sau qhov sib txawv ntawm qhov pheej yig hlau liab qab thiab kim kab txawv alloys.
Cov txheej txheem muab:
Zoo corrosion kuj dua li txheem steel
Tus nqi qis dua siab - alloy siv
Txhim kho hardness piv nrog tus qauv electroless nickel
Extended exchanger kev pab cuam lub neej
Rau ntau cov txheej txheem me me acidic, qhov sib npaug no tuaj yeem muab cov kev daws teeb meem zoo tshaj plaws.
Kev Txhim Kho Yav Tom Ntej
Kev tshawb fawb rau hauv ternary thiab quaternary electroless txheej txuas ntxiv nthuav dav.
Kev txhim kho yav tom ntej yuav suav nrog:
Txhim kho nanoparticle reinforcement
Lower porosity deposition txoj kev
Txhim kho thermal stability
Hybrid ceramic -hlau txheej
Tus kheej- kho qhov chaw chemistry
Raws li cov nroj tsuag tshuaj nrhiav cov cuab yeej siv lub neej ntev dua nrog kev nqis peev qis, cov txheej txheem electroless siab heev yuav tau txais kev lees paub dav dua.
Xaus
Electroless npib tsib xee-phosphorus-boron plating tau tshwm sim los ua ib qho kev cog lus thev naus laus zis rau txuas ntxiv lub neej kev ua haujlwm ntawm carbon steel kub exchangers nyob rau hauv ib puag ncig acidic me ntsis. Los ntawm kev sib txuas cov khoom siv electroless deposition nrog cov qauv kev pab cuam qhia los ntawm boron, lub txheej muab ib tug ntom, tsawg- porosity, heev corrosion- resistant nto muaj peev xwm tiv thaiv hlau tiv thaiv dilute sulfuric thiab hydrochloric acid raug.
Cov txiaj ntsig sib xyaw amorphous thiab nanocrystalline qauv txhim kho hardness, txo qhov porosity, thiab txhim kho hnav tsis kam piv nrog cov tsoos electroless npib tsib xee txheej. Txawm hais tias qhov ntsuas kub thiab tshuaj lom neeg muaj kev txwv, cov thev naus laus zis muaj lwm txoj hauv kev lag luam rau kev tsim kho tag nrho rau ntau qhov qis - rau - cov kev pabcuam acid hnyav.
Qhov sib ntxiv ntawm boron rau electroless npib tsib xee yog maj mam nthuav lub luag hauj lwm ntawm kev lag luam steel exchangers nyob rau hauv corrosive ua ib puag ncig. Alloying ntawm atomic scale-txawm tias nyob rau hauv ib txheej nyias- tuaj yeem hloov pauv kev khiav hauj lwm yav tom ntej ntawm ib lub raj carbon hlau zoo tib yam.
